Matrix printer

ABSTRACT

A tape printer which prints characters in the form of dots disposed in a 7 X 7 or 7 X 5 matrix has seven print elements which are arranged to be operated selectively to print one line across the tape at a time by pressing carbon paper against the tape. Each print element is provided by a projection from a pivotted member which is controlled by an associated electromagnet. These members and the electromagnets are arranged in such a way that false operation of a print element (when an adjacent print is operated) is minimised and so that the printing pressure exerted by all the print elements is approximately the same.

United States Patent [191 Barnaby et al.

[ Apr. 16, 1974 MATRIX PRINTER [75] Inventors: Bernard Sydney Barnaby, Ware;

Cyril Walter Coe, Wembley, both of England [73] Assignee: The General Electric Company Limited, London, England 22 Filed: July 6,1971

21 Appl. No.: 159,977

[52] US. Cl. 197/1 R, 101/93 C [51] Int. Cl B4lj 1/18 [58] Field of Search 197/1, 6.1; 101/93 C [56] References Cited UNITED STATES PATENTS 2,659,652 11/1953 Thompson 101/93 C X 3,109,058 lO/l963 3,333,667 8/1967 Nordm 197/1 R 3,367,469 2/1968 Fathauer 197/] R Primary Examiner-Edgar S. Burr Attorney, Agent, or Firm-Kirschstein, Kirschstein, Ottinger & Frank 5 7] ABSTRACT A tape printer which prints characters in the form of dots disposed in a 7 X 7 or 7 X 5 matrix has seven print elements which are arranged to be operated selectively to print one line across the tape at a time by pressing carbon paper against the tape. Each print element is provided by a projection from a pivotted member which is controlled by an associated electromagnet. These members and the electromagnets are arranged in such a way that false operation of a print element (when an adjacent print is operated) is minimised and so that the printing pressure exerted by all the print elements is approximately the same.

8 Claims, 6 Drawing Figures PATENTEBAPR 16 $9M 3804.224

Fig.6

C Wr-MT R Car R TOZNQ MATRIX PRINTER This invention relates to printing devices andis more particularly, but not exclusively, concerned with. tape printers.

The invention is especially concerned with printing devices of the kind in which a plurality of printing elements are arranged to be operated selectively to press print transfer medium (for example carbon paper) against paper or other material to be printed to form marks on the paper'or other material, the device having means to effect relative movement between the printing elements and the paper or other material so that a printed letter or character may be built up by successive operation of the printing elements upon such movement.

In a printing device of the kind specified according to the present invention, there are a plurality of metal strips each of which has a projection from one edge adjacent one end of the strip to form one of said printing elements, the strips lying parallel to one another and each pivotted adjacent the other end to permit limited rotation of the strip in the plane thereof, and each of said strips has an associated electro-magnet which lies to one side of the strips and a co-operating pivotted armature which lies generally transverse to the strips, a portion of each armature being arranged to abut the opposite edge to the associated strip to that from which printing element projects and the arrangement being such that, upon energisation of any one of said electromagnets during use of the device, the co-operating armature is attracted and by causing rotation of the associated strip forces only the printing element of that strip against the print transfer medium.

The edges of the strips against which the armature portions abut may be contoured so that operation of each armature only effects rotation of one of said strips.

The strips may be disposed in two groups which are pivotted as aforesaid about two axes which lie one on either side of the electro-magnets, the two groups of strips being interleaved at the ends thereof remote from 1 their pivots, that is to say in the region of the electromagnets. Furthermore, the electro-magnets may be arranged in two groups which lie on opposite sides of the strips, the co-operating armatures of different electromagnets of each group being arranged operatively to engage different strips of both groups.

Preferably said strips are non-magnetic and may each have an integral portion that acts as a spring to urge the strip towards the associated armature portion.

If the printing device is a tape printer, an electric motor may be arranged to drive the tape by way of a slipping clutch while a friction brake may be provided to arrest movement of the tape without stopping the motor.

One embodiment of a tape printer in accordance with the present invention will now be described by way of example with reference to the accompanying drawings in which FIG. 1 shows a side elevation of the printer,

FIG. 2 shows a plan view of the printer,

FIG. 3 shows an enlarged sectional elevation of the printing mechanism,

FIG. 4 shows an underneath plan view of the printing mechanism, FIG. 3 being a cross-section at the line III- III,

FIG. 5 is a cross sectional view of part of the printing mechanism at the line V-V in FIG. 3, and

FIG. 6 shows typical characters printed by the printer.

The tape printer now to be described is arranged to print a character in the form of a selection of dots disposed in a 5 X 7 (or 7 X 7) matrix, the printer having seven printing elements each of which is arranged successively to print the five (or seven) possible dots along one line of a character (i.e. along the length of the tape) as the tape is advanced.

Referring first to FIGS. 1 and 2 of the accompanying drawings, the printer essentially comprises a tape advancing unit 1 and a printer unit 2 which are mounted on opposite sides of a metal plate 3. A further plate 4 is rigidy secured to the plate 3 so as to lie generally at right angles thereto. The plate 4 carries a spool 5 of disposable typewriter ribbon 6 and a take-up spool 7 for that ribon while a coil 9 of paper tape 10 lies loosely within a container 8 that is secured to the plate 4, the container 8 being generally in the form of a box with one major side open. A pair of guides 11 and 12 are also mounted on the plate 4.

The tape advancing unit 1 comprises a pair of rollers 13 and 14 between which the ribbon 6 and tape 10 are drawn respectively from the spool 5, which is free to rotate but is not driven, and from the container 8. For the purpose of advancing the ribbon 6 and tape 10, the roller 14 is driven by an electric motor 15 by way of a wormgear 16 and a slipping clutch 17 while the roller 13 is urged towards the roller 14 by a pair of coil springs 18. The take-up spool 7 is driven from the clutch 17 by way of a band 48 and a pulley 49.

Referring now also to FIGS. 3, 4 and 5, the printer unit 2 has seven strips 19A and 196 of non-magnetic metal, for example molybdenum or stainless steel, these strips all being of the same general shape but with minor variations as will subsequently be apparent. The strips 19A to 19G are disposed in two groups, the strips 19A to 19D forming'one group and being pivotted adjacent one end about a pin 20 which lies parallel to the width of the paper tape 10 while the strips 19E. to 19G are similarly pivotted about a pin 21. The strips 19A to 19D, for example, are spaced along the pin 20 by washer's 22 so that the strips are each individually free to turn without affecting the others. Adjacent to the other end of each of the strips 19A to 19G, there is provided an integral projection 23 which extends into 'an opening 35 in the plate 3, the corresponding projections from all the seven strips lying in a straight line normally just under the roller 14 and constituting the seven printing elements of the printer. Thus a small anticlockwise rotation (in FIG. 3) of any one of the strips 19A to 19D, about the pin 20 (or a corresponding clockwise rotation of any one of the strips 19E to 19G) results in a dot being printed on the portion of the tape 10 that is then under the roller 14.

This rotation of the strips 19A to 196 is controlled by seven electro-magnets 24A to 24G each with a cooperating armature 25A to 250. (For convenience, parts associated with operation of each of the strips 19A to 19G have the same suffix letters.) The electromagnets 24A to 24G are mounted on the plate 3 with their longitudinal axes perpendicular to the plane of FIG. 4, that is to say parallel to the width of the strips 19A to 196. As is shown in FIG. 5, the electro-magnet 248, for example, is formed by a ferromagnetic core 51 which is rivetted to the plate 3 and which is embraced by a bobbin 52 that carries an operating coil 53. It may be mentioned here that the magnetic circuit associated with each of the electro-magnets 24 is completed by way of the plate 3 and side members 39 of the printer unit 2, the plate 3 and members 39 all being of ferromagnetic material.

The coils 53 of all the electro-magnets 24A to 246 are connected to terminals (not shown) carried by one of the members 39, these terminals being insulated from one another.

The armatures 25A, 25B, 25F and 24E are supported (in that order) by pin 26 and are spaced from one another by means of washer 27 so that each of these armatures may be attracted byits associated electromagnet without affecting the others. The armatures 25D, 25C and 250 are similarly supported by a pin 28 on the other side of the strips 19A to 19G to the pin 26.

Each 'of the armatures 25A to 25G is formed by a non-magnetic carrier member 29 to which a ferromagnetic member 30 is secured, for example by rivets (not shown). The seven members 30 have like fingers 31A to 31G respectively which extend under the strips 19A to 190 as shown in FIG. 4 (which is drawin with the cover plate 38, see FIG. 3, removed).

The edges of the strips 19A to 190 that are adjacent to the fingers 31A to 316 are contoured with cut-away portions, such as. the portions 32 and 33 of the strip 19C seen in FIG. 3, so as to leave each strip with a single projection 34 that normally abuts the finger 31 of the associated armature 25 for operating that strip. The cover plate 38 has a stop part 46 to hold the armatures in this position against gravity. The finger 31C, for example, thus abuts the projection 34C of the strip 19C so that, upon attraction of the armature 25C by the electro-magnet 24C, the strip 19C is rotated while the finger 31C enters cut-away portions of the strips 198 and 19D so asnot to affect them.

Each of the strips 19A to 19G has a cut-away portion 36 (see FIG. 3) leaving a flexible finger 37 which is'adjacent to the plate 3 and. which acts as a restoring Spring. Thus, upon de-energising the appropriate electro-magnet 24 afterone of the strips 19 has been rotated to force its printing element 23 against the ribbon 6, theassociated finger 37" by being pressed against the plate 3 (or an intermediate member that is not shown) urges that strip and its associated armature 25 back to their normal positions.

Although the electro-magnets 24A to 24G are arranged to exert the same attracting force on the armatures 25A to 250, the resulting pressure by the seven printing elements 23 are not all the same. This is due to differences in the distances between the points of contact of the armatures 25A to 256 with the strips 19A to 196 and (1) the pins 26 and 28 and (2) the pins 20 and 21. This variation in pressure is minimised in the printer described by arranging for the outer armatures 24A and 24D, for example, of the printing unit 2 to engage with outer strips 19A and 19D while the inner armatures 24B and 24C engage the inner strips 198 and 19C.

It is required that, when operated, the printing elements 23 shall lie in a straight line, the pins 20 and 21 being spaced to allow for the fact that the elements 23 follow arcuate paths between their normal and operated positions. To provide adjustment of this spacing, the pin 20, unlike the pin 21, is not fixed to the adjacent members 39 but is fixed to members 40 which are slidable (in the plane of FIG. 4) relative to the members 39, the members 40 being clamped in the required position by means of screws 41.

It will be appreciated that the printer described above may be used to print a character by simultaneously energising a selection of the electro-magnets 24A to 24G to form a line of dots on the paper 10 at right angles to the length of the tape and repeating this operation (five or seven times in all depending on the matrix used) as the tape 10 is advanced through the printing station. Alternatively circuitry (not shown) may be provided to energise the electro-magnets 24A to 246 sequentially so that a line of dots is slightly inclined and two examples of resulting characters (R4) are shown in FIG. 5 (using the 5 X 7 matrix). This alternative arrangement is particularly suited for usein circumstances in which the information for operating the printer is provided in serial form by a single electric signal which may be supplied by a digital computer. When operating in-this mode, the described printer has been used to print 10 characters a second and it may be mentioned that the printer is so dimensioned that each character has a height of approximately three millimetres.

In some instances it may be desirable to arrest the paper tape 10 between printing successive characters without stopping the motor 15. For this purpose, the tape advancing unit 1 (FIG. 1) is provided with a brake 42 which is arranged to'prevent the tape 10 and ribbon 6 being advanced so that the clutch 17 then slips. The brake 42 comprises an electro-magnet 43 with a fixed pole piece 44 and a movable member 45. When the electro-magnet 43 is energised to operate the brake,

the member 45 is attracted towards the pole piece 44' vso as frictionally to grip the tape 10 and ribbon 6 between the member 45 and the pole piece 44 over the length of the pole piece 44.

The construction of printer described above may be modified by the provision of a further spool which carries the paper coil 9 and which is mounted on the plate 4. In this case the container 8 is not required.

We claim:

l. A printer for a tape which constitutes an elongated web, said printer comprising:

A. tape transport means to move the tape in a direc tion parallel to its axis,

B. a printer unit over which the moving tape is movable in a plane, and

C. tape driving means for advancing the tape to and past the printer unit,

D. said printer unit being disposed in a direction perpendicularly awayfrorn one side of said plane,

E. said printer unit comprising i. a group of elongated metal strips,

ii. said metal strips being mutually spaced another and iii. being parallel to one another,

iv. means jointly pivotally supporting said metal strips adjacent one end of each of said strips about an axis parallel to said plane and perpendicular to the length of said tape so'that the free ends of said strips can oscillate toward and away from said tape and so that the strips oscillate in planes perpendicular tosaid tape plane,

v. means to limit movement of the free ends of said strip away from said tape,

from one vi. said pivotal supporting means for said strips being spaced away from said tape plane so as to lie on the same side of the tape plane as the printer unit,

vii. a plurality of magnetically attractable elongated armatures parallel to one another and spaced from the tape plane, each armature cooperating with a different strip,

viii. the axes of said armatures being transverse to the lengths of said strips,

ix. said aramtures being subdivided into two groups,

x. means pivotally supporting said armatures for mutually independent rotation about axes perpendicular to the axis of the pivotal supporting means for the strips,

xi. one of said armature pivotal axes being located on one side of said group of strips and the other of said armature pivotal axes being located on the other side of said group of strips,

xii. each of said strips having on an edge thereof remote from the armatures and adjacent the free end of said strip a printing element which strikes the tape when the strip is oscillated toward the tape,

xiii. each of said strips having intermediate its ends and on its edge opposed to the edge on which the printing element is located a portion engageable by a cooperating armature solely when the cooperating armature is operated so that operation of any one armature moves only one strip which is associated with that armature toward the tape, said portion being at a point lengthwise of the strip intermediate the strip pivotal axis and the printing element,

xiv.- two groups of electromagnets, one mounted alongside one side of the group of strips and the other mounted alongside the other side of the group of strips, said electro-magnets being disposed in the space between said armatures and said tape plane, each of said electromagnets being associated solely with a different one of said armatures and being located, and disposed to attract an associated armature, between the strips and the pivotal supporting means for the associated group of armatures,

xv. the longitudinal axes of said electromagnets being parallel to the planes in which said strips oscillate and perpendicular to said tape plane,

xvi. so that upon 'energization of anyone of said electromagnets during use of the printer unit the associatedarmature is attracted and by engagement of that armature with the opposed edge of the strip causes the printing element of that strip only to create a single mark on the tape.

2. A printer as set forth in claim 1 wherein the strips are disposed in two groups, each pivoted as aforesaid about a different axis, said strips cooperating with said armatures and having said electromagnets associated therewith, one of the strip pivotal axes being disposed on one side of the groups of electromagnets and the other of the strip pivotal axes being disposed on the other side of the groups of electromagnets, the two groups of strips being interleaved at the ends thereof remote from their affiliated pivotal axes, each armature being engageable solely with a different strip when the armature is operated.

3. A printer as set forth in claim 2 wherein at least one armature of one of said groups of armatures is engageable with one strip of one group of strips, and at least another armature of said one group of armatures is engageable with one strip of the other group of strips, and wherein at least one armature of one of the other of said groups of armatures is engageable with one strip of one group of strips, and at least another armature of said other group of armatures is engageable with one strip of the other group of strips.

4. A printer as set forth in claim 1 wherein each of said strips includes an integral springy portion which biases the strip toward the cooperating armature.

5. A printer as set forth in claim 1 wherein each of said armatures includes a projecting finger which is disposed to engage a single one of said strips as aforesaid, the fingers of the armatures'of the first and second groups of armatures overlapping one another longitudinally of said strips.

6. A printer as set forth in claim 5 wherein the first and second groups of strips consist of four and three strips, respectively.

7. A printer as set forth in claim 6 wherein the first group of strips is associated with two electromagnets of the first group and with two electromagnets of the second group, and the second group of strips is associated with two electro-magnets of the first group and one electromagnet of the second group.

8. A printer as set forth in claim 1 wherein the tape transport means includes an electric motor, drive means to engage the tape and a slipping clutchinterposed between the motor and the drive means, and

wherein the printer also includes a friction brake to arrest movement of the tape ahead of the drive means so that the tape can be stopped without stopping the motor. 

1. A printer for a tape which constitutes an elongated web, said printer comprising: A. tape transport means to move the tape in a direction parallel to its axis, B. a printer unit over which the moving tape is movable in a plane, and C. tape driving means for advancing the tape to and past the printer unit, D. said printer unit being disposed in a direction perpendicularly away from one side of said plane, E. said printer unit comprising i. a group of elongated metal strips, ii. said metal strips being mutually spaced from one another and iii. being parallel to one another, iv. means jointly pivotally supporting said metal strips adjacent one end of each of said strips about an axis parallel to said plane and perpendicular to the length of said tape so that the free ends of said strips can oscillate toward and away from said tape and so that the strips oscillate in planes perpendicular to said tape plane, v. means to limit movement of the free ends of said strip away from said tape, vi. said pivotal supporting means for said strips being spaced away from said tape plane so as to lie on the same side of the tape plane as the printer unit, vii. a plurality of magnetically attractable elongated armatures parallel to one another and spaced from the tape plane, each armature cooperating with a different strip, viii. the axes of said armatures being transverse to the lengths of said strips, ix. said aramtures being subdivided into two groups, x. means pivotally supporting said armatures for mutually independent rotation about axes perpendicular to the axis of the pivotal supporting means for the strips, xi. one of said armature pivotal axes being located on one side of said group of strips and the other of said armature pivotal axes being located on the other side of said group of strips, xii. each of said strips having on an edge thereof remote from the armatures and adjacent the free end of said strip a printing element which strikes the tape when the strip is oscillated toward the tape, xiii. each of said strips having intermediate its ends and on its edge opposed to the edge on which the printing element is located a portion engageable by a cooperating armature solely when the cooperating armature is operated so that operation of any one armature moves only one strip which is associated with that armature toward the tape, said portion being at a point lengthwise of the strip intermediate the strip pivotal axis and the printing element, xiv. two groups of electromagnets, one mounted alongside one side of the group of strips and the other mounted alongside the other side of the group of strips, said electro-magnets being disposed in the space between said armatures and said tape plane, each of said electromagnets being associated solely with a different one of said armatures and being located, and disposed to attract an associated armature, between the strips and the pivotal supporting means for the associated group of armatures, xv. the longitudinal axes of said electromagnets being parallel to the planes in which said strips oscillate and perpendicular to said tape plane, xvi. so that upon energization of any one of said electromagnets during use of the printer unit the associated armature is attracted and by engagement of that armature with the opposed edge of the strip causes the printing element of that strip only to create a single mark on the tape.
 2. A printer as set forth in claim 1 wherein the strips are disposed in two groups, each pivoted as aforesaid about a different axis, said strips cooperating with said armatures and having said electromagnets associated therewith, one of the strip pivotal axes being disposed on one side of the groups of electromagnets and the other of the strip pivotal axes being disposed on the other side of the groups of electromagnets, the two groups of strips being interleaved at the ends thereof remote from their affiliated pivotal axes, each armature being engageable solely with a different strip when the armature is operated.
 3. A printer as set forth in claim 2 wherein at least one armature of one of said groups of armatures is engageable with one strip of one group of strips, and at least another armature of said one group of armatures is engageable with one strip of the other group of strips, and wherein at least one armature of one of the other of said groups of armatures is engageable with one strip of one group of strips, and at least another armature of said other group of armatures is engageable with one strip of the other group of strips.
 4. A printer as set forth in claim 1 wherein each of said strips includes an integral springy portion which biases the strip toward the cooperating armature.
 5. A printer as set forth in claim 1 wherein each of said armatures includes a projecting finger which is disposed to engage a single one of said strips as aforesaid, the fingers of the armatures of the first and second groups of armatures overlapping one another longitudinally of said strips.
 6. A printer as set forth in claim 5 wherein the first and second groups of strips consist of four and three strips, respectively.
 7. A printer as set forth in claim 6 wherein the first group of strips is associated with two electromagnets of the first group and with two electromagnets of the second group, and the second group of strips is associated with two electro-magnets of the first group and one electromagnet of the second group.
 8. A printer as set forth in claim 1 wherein the tape transport means includes an electric motor, drive means to engage the tape and a slipping clutch interposed between the motor and the drive means, and wherein the printer also includes a friction brake to arrest movement of the tape ahead of the drive means so that the tape can be stopped without stopping the motor. 